Traditional key padlocks or programmable mechanical locksets have been used to secure areas including buildings, rooms and cabinets. In these and other applications, access control systems and methods have been implemented to grant access only to authorized users and to update access permissions. The traditional locks have been developed over centuries to be sturdy and moderately difficult to bypass, and to function reliably without frequent inspection or maintenance. However, the traditional access control systems and methods are increasingly costly as a function of the security provided. Additionally, regardless of the level of security, traditional locks are very costly to properly maintain. For example, when a former user no longer is authorized, or when a key is lost, each potentially vulnerable mechanical lockset should be rekeyed or replaced. Consequently, updated access codes or keys must be distributed to all users who still should have access. Therefore, there is a need for improved access control systems and methods that can be cheaply and reliably maintained. In particular, there is a need for improved access control systems and methods that permit rapid and inexpensive updates of access permissions.
Electronic key systems have been used over the years and have proven to be a reliable mechanism for access control solutions. Exemplary electronic key systems are disclosed in U.S. Pat. No. 4,988,987, issued Jan. 29, 1991; U.S. Pat. No. 6,047,575, issued Apr. 11, 2000; U.S. Pat. No. 6,989,732, issued Jan. 24, 2006; U.S. patent application Ser. No. 10/893,648, published Mar. 10, 2005; and U.K. Pat. App. GB 2 144 483, published Mar. 6, 1985. Another electronic key system, fully commercialized in the hotel industry, is the VingCard® product line. However, the exemplary systems, despite their commercial success, do not to our knowledge provide reliable and secure means for rapidly updating access permissions in a distributed security application, wherein individual locks are installed in various far-flung locations so that capital costs or physical constraints prohibit placing the individual locks in direct communication with a central database or bringing the locks to a central location for reprogramming.
Therefore, there is a need for improved electronic key systems and methods capable to rapidly update access permissions in a distributed security application.